The spelling of "sallowest" can be explained through its IPA phonetic transcription /ˈsæl.oʊ.ɪst/. The first syllable is pronounced with the "æ" sound, as in "cat," followed by the "l" sound. The second syllable has the "oʊ" sound, as in "go," and the third syllable has the "ɪ" sound, as in "it." The "-est" ending indicates that it is the superlative form of the adjective "sallow," meaning pale or yellowish. Therefore, "sallowest" means the most pale or yellowish.
The word "sallowest" is derived from the adjective "sallow", which has its roots in the Old English word "salu". "Salu" initially referred to the pale or sickly color of one's skin, particularly a yellowish or sickly yellow hue. Over time, "salu" evolved into "sallow", retaining its association with an unhealthy or sick appearance. The suffix "-est" is added to "sallow" to form the superlative degree, indicating the extreme or highest degree of sallowness.